Health ministers, charities, donors and private sector companies working in the family planning business will discuss increasing the global availability of contraceptives and how to empower women so they have more choices about sex.

Mr Mitchell said: "The health and rights of girls and women are front and centre of Britain's aid programme. Being able to plan the size of her family is a fundamental right that we believe all women should have.

"British support will mean that millions of women who are currently unable to access or use family planning information, services and supplies will be able to decide, freely and for themselves, whether, when and how many children to have.

"Women who are able to use modern contraceptives are better able to care for their families and are more likely to be economically active, benefiting their families and their communities alike."

It is estimated that 220 million women around the world do not have access to contraceptives or information on them.

In some countries women need written consent from their husbands before they can talk to a doctor about contraception while in others, family planning services are not offered to adolescents or unmarried women.

In developing countries, contraceptives are frequently out of stock when women try to get them.

Delegates at the summit are hoping to get 120 million women better access to contraceptives, information and services by 2020.

Mr Mitchell will also commit £516 million to this cause.

Every two minutes a woman dies from pregnancy-related complications, a DFID spokesman said.

A recent report from Save the Children suggests that pregnancy is the biggest killer of teenage girls worldwide.

The charity said that every year one million teenage girls die or are injured because of pregnancy or childbirth.

The summit, which is being held later today in central London, is expected to be attended by delegates from 20 to 25 countries, including the US, India, Ethiopia, Nigeria and Tanzania.

Aides to Mr Mitchell said he is passionate about bringing the issue to the global stage. Mr Mitchell visited Malawi in June to see first-hand the effects of limited contraception.

Mr Mitchell contacted Melinda Gates after she said that family planning was one of her "top priorities".

Mrs Gates said: "When I travel and talk to women in developing countries, they all tell me that they want access to contraceptives to be able to plan their families.

"These women want to raise healthy and educated children that can contribute to building prosperous communities.

"I'm hopeful that the London Summit on Family Planning our foundation is co-hosting with the UK's Department for International Development will galvanise a global movement to give 120 million more women in the poorest countries access to the contraceptives they want.

"All women and girls should have the right to determine their own future."

The Gates Foundation and the US government is expected to pledge millions of dollars on developing more efficient forms of contraception.

The health minister of Bangladesh, Humayun Kabir, who will be attending the summit, said: "The summit, I hope, would make every one aware how important it is to renew our focus on family planning.

"We have seen very recently, the population of the world crossing seven billion. Though the world has so far been able to feed this continuously growing human species, but resources are put under severe stress for a developing country like ours in managing our economy and environment.

"It is possible to arrest this growth and concerted efforts can help us which can be channelled through this summit. I hope we would see specific commitments from the world leaders for addressing this issue.

"While the leaders from the developing country can set very specific goals and targets, the developed world can come forward to reduce the resource gap. And commitments from both can save the human society and the world we live in and our environment."